In English, whether you say a vowel a little longer or a little shorter almost never changes the meaning of a word. In Japanese it constantly does. Vowel length is phonemic: holding a vowel for one extra beat produces a completely different word. ゆき is "snow"; ゆうき is "courage". Getting length wrong is not a minor accent flaw — it is saying the wrong word. This page shows you the contrasts, how length is written, and the one mental switch that fixes it: count beats, do not stress.
Length changes the word
A long vowel is simply a vowel held for two morae (two beats) instead of one — the same vowel, the same pitch, just held twice as long. Because Japanese counts morae (see The Mora), that extra beat is a real, meaning-bearing unit. Here are three pairs where length is the only difference:
ゆき vs ゆうき — 雪（ゆき）"snow" (yu-ki, 2 morae) versus 勇気（ゆうき）"courage" (yu-u-ki, 3 morae).
雪が降っています。
yuki ga futte imasu
It's snowing. — 雪（ゆき）: short u, two beats.
勇気を出してください。
yūki o dashite kudasai
Please be brave. — 勇気（ゆうき）: long ū, three beats. One extra beat, a whole new word.
ここ vs こうこう — ここ "here" (ko-ko, 2 morae) versus 高校（こうこう）"high school" (ko-o-ko-o, 4 morae).
切符はここで買えます。
kippu wa koko de kaemasu
You can buy tickets here. — ここ: two short o's.
高校の時、サッカーをしていました。
kōkō no toki, sakkā o shite imashita
In high school I played soccer. — 高校（こうこう）: two long ō's, four beats.
おばさん vs おばあさん — おばさん "aunt / middle-aged woman" (o-ba-sa-n, 4 morae) versus おばあさん "grandmother / old woman" (o-ba-a-sa-n, 5 morae).
うちのおばあさんは元気です。
uchi no obāsan wa genki desu
My grandmother is doing well. — 長い ā: obāsan, five beats.
隣のおばさんに挨拶しました。
tonari no obasan ni aisatsu shimashita
I greeted the lady next door. — おばさん, four beats; drop the extra あ and you'd be calling her 'grandmother'.
The fix: count beats, do not stress
Here is why this is hard for English speakers specifically. English does lengthen vowels — but only as a side effect of stress. The vowel in record (noun) is longer than in record (verb) because it is stressed: louder, higher, and longer all at once. English has no way to make a vowel purely longer without also making it stronger.
So when an English speaker meets ゆうき, the instinct is to stress the long part — "yoo-OO-ki" — pounding it louder and higher. That is wrong. A Japanese long vowel is the same vowel, at the same volume and the same pitch, simply held for a second even beat. Think of it as counting: yu — u — ki, two equal beats on the "u", not one loud one.
How length is written
Long vowels have consistent spellings, which is lucky — the writing tells you where to hold. In hiragana, a long vowel is usually written by adding a vowel kana; in katakana it is written with the bar ー (the chōonpu).
| Long vowel | Usual hiragana spelling | Example |
|---|---|---|
| ā | あ + あ | お母さん おかあさん okāsan (mother) |
| ī | い + い | お兄さん おにいさん onīsan (older brother) |
| ū | う + う | 空気 くうき kūki (air) |
| ē | え + い (usually); え + え (rare) | 先生 せんせい sensei (teacher); お姉さん おねえさん onēsan (older sister) |
| ō | お + う (usually); お + お (rare) | お父さん おとうさん otōsan (father); 大きい おおきい ōkii (big) |
| any (katakana) | vowel + ー | コーヒー kōhī (coffee) |
Two spellings hide a trap for the ear. Long ō is usually spelled おう — but the う is not a separate "u" sound; it just means "hold the お". So おとうさん is o-tō-san (long o), not "o-to-u-san", and ありがとう ends in a long ō, not a spoken "u". Likewise long ē is usually spelled えい, and せんせい is pronounced with a held "e" (roughly sensē), not "sen-say" with a y-glide.
お父さんは今日いますか。
otōsan wa kyō imasu ka
Is your dad home today? — お父さん（おとうさん）: the おう is a long ō, not 'o-u'.
どうもありがとうございました。
dōmo arigatō gozaimashita
Thank you very much. (polite) — every おう here is a held long ō, no spoken 'u'.
The choice between おう and おお (and between えい and ええ) is a spelling question, not a sound question — both are just long vowels. For which words take which, see Long Vowels in Hiragana and Spelling Long Vowels: おう vs おお.
The katakana bar ー
In katakana — mostly loanwords — length is written with the single bar ー, whichever vowel it lengthens. This is where a dropped beat produces a famously different word:
ビル vs ビール — ビル "building" (bi-ru, 2 morae) versus ビール "beer" (bī-ru, 3 morae).
ビールを一本ください。
bīru o ippon kudasai
One beer, please. — ビール with the ー: three beats, bī-ru.
あのビルは新しいです。
ano biru wa atarashii desu
That building is new. — ビル without the bar: two beats. Order the wrong one and you get a building, not a beer.
コーヒーとラーメン、どっちがいい？
kōhī to rāmen, dotchi ga ii?
Coffee or ramen — which do you want? (casual) — コーヒー kōhī and ラーメン rāmen each hold a long vowel at the bar.
For the deep end, length can even distinguish words that differ only in where the beats fall: 病院（びょういん）byōin "hospital" is four morae (byo-o-i-n), while 美容院（びよういん）biyōin "beauty salon" is five (bi-yo-o-i-n). Same-looking kana, one extra beat, opposite errand.
Common mistakes
勇気
❌ yuki (long vowel clipped short)
Wrong: shortening ゆうき turns 'courage' into 雪 'snow'.
勇気
✅ yūki (yu-u-ki, held long)
Right: hold the u for a second even beat.
ここ
❌ kōkō (short vowels stretched)
Wrong: lengthening ここ makes it sound like 高校 'high school'.
ここ
✅ koko (two short beats)
Right: two crisp, short o's, no holding.
おばあさん
❌ o-ba-BAA-san (long vowel stressed)
Wrong: pounding the long あ louder and higher, English-style.
おばあさん
✅ obāsan (held, even, level)
Right: the long あ is the same 'a' held for a second beat at the same pitch.
ありがとう
❌ arigato-u (う voiced as a separate 'u')
Wrong: reading the おう spelling as 'o' plus a distinct 'u'.
ありがとう
✅ arigatō (long ō, no spoken 'u')
Right: the う just lengthens the お into a held ō.
ビール
❌ biru (bar ignored, 2 beats)
Wrong: dropping the ー turns 'beer' into ビル 'building'.
ビール
✅ bīru (bī-ru, 3 beats)
Right: the ー adds a full beat — bi-i-ru.
Key takeaways
- Vowel length is phonemic: ゆき/ゆうき, ここ/こうこう, おばさん/おばあさん are different words that differ only in a held beat.
- A long vowel is two morae — the same vowel, same pitch, held twice as long. Count it, don't stress it.
- Hiragana writes length by adding a vowel (usually おう for long ō, えい for long ē); katakana uses the bar ー. The う in おう and the い in えい are held vowels, not spoken "u"/"y".
- The おう/おお and えい/ええ choice is spelling only — both are plain long vowels; see the hiragana long-vowel page.
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Start learning Japanese→Related Topics
- Long Vowels in HiraganaN5 — How hiragana spells long vowels by adding a vowel kana — including the えい/おう twist — and why vowel length is phonemic (おばさん 'aunt' vs おばあさん 'grandmother').
- The Mora: Japanese TimingN5 — The mora (拍) is the beat that Japanese is timed by — every kana is one, and long vowels, the small っ, and the moraic ん each add a full beat of their own.
- Spelling Long Vowels: おう vs おお, えい vs ええN4 — The spelling decision every hiragana long o and long e forces on you — write おう or おお, えい or ええ — with the finite, memorizable list of native words that break the default and the historical reason they exist.